Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
135/80r18 vs 275/40r20 Tire Comparison Side By Side
  135/80-18 275/40-20 Difference
Diameter inches (mm) 26.5 (673.2) 28.66 (728) 2.16 (54.8) 8.1%
Width inches (mm) 5.31 (135) 10.83 (275) 5.51 (140) 103.7%
Circum. inches (mm) 83.26 (2114.92) 90.04 (2287.08) 6.78 (172.16) 8.1%
Sidewall Height inches (mm) 4.25 (108) 4.33 (110) 0.08 (2) 1.9%
Revolutions per mile (km) 760.95 (472.83) 703.67 (437.24) -57.28 (-35.59) -7.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.63 mph (34.81 km/h)
25 mph (40.23 km/h)27.04 mph (43.51 km/h)
30 mph (48.28 km/h)32.44 mph (52.21 km/h)
35 mph (56.33 km/h)37.85 mph (60.91 km/h)
40 mph (64.37 km/h)43.26 mph (69.61 km/h)
45 mph (72.42 km/h)48.66 mph (78.32 km/h)
50 mph (80.47 km/h)54.07 mph (87.02 km/h)
55 mph (88.51 km/h)59.48 mph (95.72 km/h)
60 mph (96.56 km/h)64.88 mph (104.42 km/h)
65 mph (104.61 km/h)70.29 mph (113.12 km/h)
70 mph (112.65 km/h)75.7 mph (121.82 km/h)
75 mph (120.7 km/h)81.11 mph (130.53 km/h)
80 mph (128.75 km/h)86.51 mph (139.23 km/h)
85 mph (136.79 km/h)91.92 mph (147.93 km/h)
90 mph (144.84 km/h)97.33 mph (156.63 km/h)
95 mph (152.89 km/h)102.73 mph (165.33 km/h)
100 mph (160.93 km/h)108.14 mph (174.04 km/h)

Gear Ratio / RPMs for New Tire (@ 65 mph)
2.35 2.73 2.94 3.07 3.21 3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17
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